The technology of the present disclosure relates to an image reading device and an image forming apparatus, and more particularly, to an image reading device which has a document fixed reading mode and a document conveying reading mode as a document reading mode, and an image forming apparatus.
A document reading mode is classified into two modes of a document fixed reading mode and a document conveying reading mode. In the document fixed reading mode, a document placed on a contact glass is fixed by a platen mat and the like and a reading unit is moved in a sub-scanning direction, so that the document is read. In the document conveying reading mode, a reading unit is fixed at a prescribed position and the document is read while conveying the document on the reading unit. In an image reading device having both the document fixed reading mode and the document conveying reading mode, a contact glass is classified into two glasses of a contact glass for document fixed reading and a contact glass for document conveying reading, and a document separation member for separating a read document from the contact glasses and discharging the read document is provided between the glasses.
In general, for the reading unit, a CIS (Contact Image sensor) type reading sensor extending in a main scanning direction is used. Since the CIS type reading sensor has a very shallow depth of field, the CIS type reading sensor makes close contact with the contact glass via a sliding member such as a slider. In a position at which the sliding member makes contact with the document separation member between the glasses, since the posture of the CIS type reading sensor is not stable, good document reading is not possible. Therefore, at the time of document conveying reading or reading of a white reference member, it is necessary to prevent the sliding member from making contact with the document separation member, and there is a problem that an image reading device increases in size. In order to overcome such a problem, there has been proposed an image reading device having a configuration in which the document separation member does not protrude toward the rear surface of the contact glass. According to the image reading device, since the movement of a reading unit is not disturbed by the document separation member, the image reading device can be made in a small size.